title: Effects of amelogenins on angiogenesis-associated processes of endothelial cells.
abstract: OBJECTIVE
  To study the effects of an amelogenin mixture on integrin-dependent adhesion, DNA synthesis and apoptosis of cultured human dermal microvascular endothelial cells and angiogenesis in an organotypic assay.
  
  
  METHODS
  Immobilised antibodies against specific integrins (alpha-1, alpha-2, alpha-3, alpha-4, alpha-5, alpha-v, ß1, ß2, ß3, ß4, ß6, alpha-vß3, alpha-vß5 and alpha-5ß1) were used to capture treated human dermal microvascular endothelial cells, which were detected colourimetrically. DNA synthesis of the cells was monitored by 5-bromo-2'- deoxyuridine incorporation and apoptosis by a TdT-mediated dUTP nick-end labelling technique. Tubule formation from aortic arches of 13-d-old chick embryos were followed over 48h.
  
  
  RESULTS
  The amelogenin mixture increased microvessel outgrowth by 76% (p < 0.01, n=12) from the aortic explants. Also, amelogenins increased the adhesion (p < 0.01, n = 5) by multiple angiogenesis associated integrin subunits and alpha-vß3, alpha-vß5 and alpha-5ß1 heterodimers on human dermal microvascular endothelial cells at a non-mitogenic concentration (100 µg/ml). Conversely, amelogenins at 1,000 µg/ml decreased microvessel formation possibly due to attenuation of corresponding integrins despite increasing (p < 0.001, n = 8) DNA synthesis. No significant apoptosis was detected in human dermal microvascular endothelial cells cultured on Matrigel with and without amelogenins.
  
  
  CONCLUSIONS
  Increased surface expression of integrins on endothelial cells may contribute to the proangiogenic property of amelogenins.
authors.affiliation: Department of Biomaterials, Sahlgrenska Academy at the University of Gotheburg, Göteborg, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Almqvist
authors.forename: H K
authors.initials: HK
authors.lastname: Kleinman
authors.forename: M
authors.initials: M
authors.lastname: Werthén
authors.forename: P
authors.initials: P
authors.lastname: Thomsen
authors.forename: M S
authors.initials: MS
authors.lastname: Agren
mesh_terms: D053523:Amelogenin; D002478:Cells, Cultured; D042783:Endothelial Cells; D004730:Endothelium, Vascular; D006801:Humans; D016023:Integrins; D018919:Neovascularization, Physiologic
chemical_list: D053523:Amelogenin; D016023:Integrins